The present invention relates to a notching machine having a rotation assembly with a central axis of rotation, the rotation assembly carrying a hub, spindle and tool that share a common axis and are selectively offset to orbit around the central axis to permit the tool to form notches of varying radii into a workpiece such as a tube, pipe or rod.
Many modern buildings and products utilize interconnected pipes, tubes and rods. Buildings frequently use tubes to form handrails, bicycle racks and other fixtures as shown in FIG. 1. These handrails are formed by a variety of different diameter tubes. The end of one tube is joined to the sidewall of another. The ends of the tubes are notched to form a smooth joint where one tube is welded or otherwise secured to the other. Chemical and food processing plants incorporate elaborate piping systems to efficiently move and dispense fluids throughout the plant. A portion of such a piping system is shown in FIG. 2. One pipe has a hole in its sidewall and the other pipe is angled so that the fluid in the pipe will smoothly flow into the other. The end of the pipe is notched to flushly mate against the sidewall of the other to help achieve a smooth flow of fluid through the piping system. Manufacturing plants produce a wide variety of consumer products formed from interconnected tubes, such as lawn furniture, play ground equipment, automobile chassis, airplane fuselages scaffolding and crane booms.
To assemble these building fixtures, piping systems and consumer products, a number of tubes, pipes, rods or other types of workpieces are cut to their appropriate length. A notching machine is then used to cut or otherwise form a notch into one or both ends of each tube or workpiece. These tubes are then assembled to form the desired product. The notched end of one part smoothly mates with and is welded or otherwise joined to the sidewall of another part to form an integral fixture, pipe system or product. Conventional notching machines typically incorporate a vice that holds the tube, and a spindle that holds and rotates a tool about its axis. The common axis of this spindle and tool remains fixed, or moves in a linear direction toward the tube to form a notch in its end. Each notch has the same radius as the tool used to form the notch.
A problem with conventional notching machines is their excessive operating costs. Each tool has a given diameter or radius and is only capable of forming a notch having that same radius. A full contingent of twenty or more different radius tools may be needed to form the various notches required at a given construction site of manufacturing plant. This dramatically increases the operating cost of the machine because each tool costs between $100 and $1,000. Yet, a single handrail, piping system, or product may require a variety of different diameter tubes, pipes or rods that must be notched to suit a particular joint geometry. This problem is compounded by the fact that construction sites and manufacturing plants frequently have several different projects or product runs going simultaneously. One project may require several different notch sizes and shapes, and each notch may need to be formed by a cutting or milling tool and then finished by a grinding or polishing tool. As a result, the notching machine must include a full contingent of each type of tool, which multiplies the operating costs associated with the machine.
An additional problem with conventional notching machines is their inefficiency. The machine operator must turn off the machine or stop production to change the tool each time a different radius notch or opening is cut. This constant interruption in production results in significant down time and reduced worker and machine efficiency.
A further problem with conventional notching machines is their limited capabilities. Any given notching machine may only be able to make one or two types of notches or joints. While one machine may be capable of forming a notch in the end of a tube, that machine may not be suitable for performing a plunge cut into the tube. The machine may also be incapable of forming a snap fit type notch into the tube. As a result several expensive machines are required to perform the various types of work needed at modern construction sites and manufacturing plants.
A still further problem with conventional notching machines is that they are heavy, bulky and awkward to move. Yet, some projects or product runs may require hundreds of individual component parts that must be brought to the notching machine. Hauling bulky quantities of parts from one end of a construction site or plant to another is not only labor intensive, but can also result in needless injury to the workers.
The present invention is intended to solve this and other problems.
The present invention relates to a notching machine for forming a radial notch into a workpiece, such as the side or end of a tube, pipe or rod. The notching machine includes a workpiece positioning assembly, a hub and spindle assembly, an offset mechanism, a hub drive mechanism and a spindle drive mechanism. The workpiece positioning assembly includes a cross slide table and a vice for gripping and positioning the workpiece into a desired position. The hub and spindle assembly includes a hub that is rotatably mounted on a hub rotation assembly. The hub rotation assembly rotates about a central axis of rotation. The hub carries a spindle and its tool. The hub, spindle and tool share a common axis. This common axis is the axis of rotation of the spindle and tool. The hub, spindle and tool can be aligned in an in-line or offset manner with respect to the central axis. The offset mechanism includes an offset adjustment screw that offsets the common axis of the hub, spindle and tool a desired distance from the central axis. When the hub and spindle are offset and rotated about the central axis, the tool orbits about the central axis through a desired circular path of travel. The radius of the notch cut by the tool is adjusted by adjusting the amount of offset. The hub drive mechanism is hand driven by the machine operator via a hand wheel. The spindle drive mechanism is driven by an electric motor that is directly linked to the spindle. The motor is secured to a frame of the machine via a torque arm.
An advantage of the present notching machine invention is its low operating cost. Although a cutting, milling, grinding or polishing tool may have a single given diameter or radius, the present notching machine is able to use that tool to cut or otherwise form notches having a variety of radii. This is accomplished by varying the distance the spindle is offset from the central axis of the hub rotation assembly. For example, a notching machine with a maximum offset of one inch can use a single one inch diameter tool to form notches varying between one to three inches. Instead of needing a full contingent of twenty or more tools, only two or three tools may be needed to form all the various radii notches required by a wide variety of fixtures, piping systems or products. This benefit is multiplied at construction sites and manufacturing plants that use numerous types of tools. Not only are fewer cutting tools needed, but fewer milling, grinding or polishing tools are needed as well.
Another advantage of the present notching machine invention is its versatility. The notching machine is designed to hold and machine a wide variety of workpieces, such as tubes, pipes and rods. The workpiece can have a round, square, rectangular of other cross sectional shape. The notching machine can also form a notch or opening in the end or side of the workpiece. The workpiece can be held firmly to the frame of the machine by a cross slide table and vice. In some situations, only the movement of the tool through its orbiting path of travel is need to create the desired notch or opening. In other situations, the tool does not move, and the workpiece is moved along a desired path of travel by the cross slide table. In other situations, a combination of tool and workpiece movement are combine to produce the desired notch or opening. For example, the present notching machine can form both notches and plunge cuts into a tubular workpiece. The machine is also capable of forming a snap fit type notch into the end of a tube, pipe or rod. This versatility allows a single notching machine to be used for a wide variety of fixtures, piping systems and products.
A further advantage of the present notching machine invention is its portability. The compact size and relatively light weight design of the present notching machine achieves a degree of portability that allows it to be brought directly to the area of the construction site or manufacturing plant where the fixture, piping system or product is being made or installed. The expense and danger of hauling large quantities of bulky or unwieldy workpieces through a crowded construction site or manufacturing plant are eliminated or dramatically reduced. The machine is specifically designed to fit into the service elevators of most construction sites and manufacturing plants. This versatility and portability also combine to dramatically reduce the operating cost associated with the present notching machine.
A still further advantage of the present notching machine is its precision and safety. The notching machine includes a hub drive mechanism that is manually operated by a hand wheel. The operator is able to control the rate of each cut to ensure the quality of each cut. The hub drive mechanism also has a one-way clutch that only permits the tool to be advance into the workpiece in the same rotational direction as the tool. This one-way clutch helps prevent the tool from grabbing or biting into the workpiece as the workpiece is being cut. The clutch also prevents the machine operator form inadvertently feeding the tool into the workpiece from the wrong direction, which can cause the tool to bit into the workpiece and break the tool. This digging or biting can cause the tool to jump or rapidly accelerate through the workpiece, which can damage the workpiece and injure the machine operator.